Ignition distributor housing and resiliently attached distributor base plate

ABSTRACT

An ignition distributor for use in an internal combustion engine spark ignition system including a hollow casing formed internally with a support surface and a groove. The groove extends radially into the wall of the casing from the support surface. The distributor further includes a contact breaker assembly mounting plate which is supported on the support surface, and which includes a peripheral region capable of being engaged in a region of the groove in the casing wall. A spring member is provided which urges the mounting plate both downwardly onto the support surface and transversely so that the region of the plate engages in the corresponding region of the groove.

United States Patent Tromans [451 Feb. 26, 1974 1 IGNITION DISTRIBUTOR HOUSING AND RESILIENTLY ATTACHED DISTRIBUTOR BASE PLATE [30] Foreign Application Priority Data Jan. 15, 1972 Great Britain 2,026/72 ['52] US. Cl 5700729312, ZOO/19R, ZOO/31131 [51] Int. Cl. H0lh 9/02 [58] Field of Search 200/19 R, 31 DP, 168 R [56] References Cited UNITED STATES PATENTS 11/1969 .Cooksey 200/19 R 6/1948 Aldridge 200/31 DP X Primary Examiner.lames R. Scott Attorney, Agent, or FirmH0lman & Stern [57] ABSTRACT An ignition distributor for use in an internal combustion engine spark ignition system including a hollow casing formed internally with a support surface and a groove. The groove extends radially into the wall of the casing from the support surface. The distributor further includes a contact breaker assembly mounting plate which is supported on the support surface, and which includes a peripheral region capable of being engaged in a region of the groove in the casing wall. A spring member is provided which urges the mounting plate both downwardly onto the support surface and transversely so that the region of the plate engages in the corresponding region of the groove.

8 Claims 3 Drawing Figures IGNITION DISTRIBUTOR HOUSING AND RESILIENTLY ATTACHED DISTRIBUTOR BASE PLATE This invention relates to ignition distribotors for use in internal combustion engine spark ignition systems.

An ignition distributor according to the invention includes, a hollow casing formed internally with a support surface and a groove, the groove extending radially into the wall of the casing from the support surface, a contact breaker assembly mounting plate supported on the support surface and having a peripheral region engageable in the groove, and a resilient member engaging the casing and the mounting plate and urging the mounting plate both downwardly onto the support surfaceand transversely so as to engage said peripheral region in the groove.

Preferably the peripheral region of the mounting plate is chamfered so as to wedgingly engage the walls of the groove.

Conveniently the resilient member is a spring steel strip of generally L shaped configuration, one limb of the strip engaging the casing and the other limb engaging the mounting plate.

Preferably the free end of the one limb engages a shoulder on the inner surface of the casing.

Conveniently the other limb is secured to the mounting plate by a screw fastening device.

Alternatively the other limb of the resilient member includes a portion extending into an aperture in the mounting plate the portion abutting the wall of the aperture.

Conveniently, the mounting plate is provided, opposite the peripheral region, with a slot extending from the periphery of the mounting plate along a chord of the mounting plate so as to define a resilient ear integral with the mounting plate, clamping means being provided for urging the resilient ear in a direction away from the remainder of the base plate so as to engage the resilient ear in the groove and so aid the action of the resilient member in clamping the mounting plate in position in the casing.

Preferably the periphery of the resilient car which engages in the groove is chamfered so as to wedgingly engage the walls of the groove.

Conveniently the clamping means for urging the resilient ear in a direction away from the remainder of the mounting plate comprises a tapered screw which extends through the slot, the tapered screw serving also to secure the resilient member to the mounting plate.

One example of the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a diagrammaticrepresentation of part of an ignition distributor,

FIG. 2 is a plan view of an alternative form of contact breaker assembly mounting plate for the distributor to that shown in FIG. 1, and

FIG. 3 is a side view enlarged of a modification of the spring strip shown in FIG. 1.

Referring first to FIG. 1, the distributor includes a hollow metal casing 1 1 formed internally with a radially inwardly directed shoulder 12. The shoulder 12 extends into the wall thickness of the casing 11, and together with an inclined surface 14 defines a peripheral groove 13. Seated on the shoulder 12 is a contact breaker assembly mounting plate 15, which, in use,

supports a conventional contact breaker assembly. The mounting plate 15 is annular, and the cam shaft of the distributor extends through the central hole of the plate 15 in the usual manner. A region 16 of the periphery of the plate 15 is chamfered, and positioned generally diametrically opposite the region 16 is a resilient member 17 in the form of a generally L-shaped strip of spring steel. The free end of the upright limb 17a of the member 17 is engaged with a step 18 formed in the wall of the casing 11, and the other limb 17b of the member 17 is secured to the plate 15 by means of a screw 19. The arrangement of the member 17, the plate 15 and the casing 11 is such that when secured in position the resilient member 17 urges the plate 15 both downwardly onto the shoulder 12, and transversely so that the chamfered region 16 of the periphery of the plate 15 wedgingly engages the V shaped groove 13. The resilient member 17 is secured in position in the following manner. The free end of the limb 17a is engaged beneath the step 18, and the free end of the limb 17b touches the plate 15. However, the aperture in the limb 17b for the screw 19 is at this stage to the right of the corresponding aperture in the plate 15, and moreover, the limb 17b is not parallel to the plate. Thus in order to insert the screw 19 through the limb 17b and into the plate 15 the member 17 must be flexed to move the limb 1712 both downwardly, and to the left. Thus when the screw 19 is inserted through the aperture in the limb 17b, and into the corresponding hole in the plate 15 to secure the member 17 in position, then the member will urge the plate 15 both downwardly and transversely as required.

The modified resilient member 17 shown in FIG. 3 is again formed from spring strip and is of generally L- shaped configuration having a pair of limbs 27a, 27 b. The free end of the upright limb 27a is bent out of the plane of the remainder of the limb 27a and is engaged under the step 18 in use. The limb 27b is formed with a hole through which the fixing screw extends in use to secure the member 27 in position. The limb 27a is formed with a V-shaped region intermediate its ends the V-shaped region enhancing the resilient action of the member 27 in urging the plate 15 downwardly and transversely. As an alternative to the assembly sequence described with reference to member 17 the member 27 is secured in position by firstly fixing the limb 27b to the plate 15 by means of a screw. Thereafter the limb 27a is flexed to engage its free end with the step 18 of the casing. It will be appreciated that the member 17 could be secured in position in this manner and that the member 27 could, if desired, be secured in position by the method described with reference to member 17.

It will be appreciated, that the dimensions of the plate 15, the shoulder 12, and the groove 13 are so chosen that the plate 15 can be inserted into the casing to rest on the shoulder 12, and can still be moved sufficiently far to wedgingly engage the region 16 of the periphery of the plate with the groove 13 without the opposite edge of the plate 15 leaving the shoulder 12.

In a modification (FIG. 2) the mounting plate 15 is formed with a slot 21 which extends from the periphery of the plate 15 along a chord thereof to define a resilient ear 22 integral with the plate 15. The chamfered region 16 is diametrically opposite the ear 2 2, and moreover the chamfered region 16 projects radially outwardly from the periphery edge of the plate 15. The

arcuate edge of the car 22 is chamfered, and with the exception of the ear 22 the periphery of the plate over the plate. The plate is then dropped into the distributor casing and is supported on the shoulder 12. Thereafter a tapered screw is then inserted into the slot 21 and is rotated. The action of the tapered screw in the slot 21 flexes the ear 22 outwardly away from the remainder of the plate, so that the chamfered edge of the ear22 engages in the groove 13 at one side of the casing and the chamfered region 16 of the plate engages in the groove 13 at the opposite side of the casing. The tapered screw which is inserted through the slot 21 also serves to hold in position the resilient member 17, or 27 the combined action of the resilient member and the ear 22 serving to secure the mounting plate in position within the casing.

A conventional contact breaker assembly is mounted on the mounting plate 15 either directly, or through the intermediary of an angularly movable plate to facilitate adjustment in the ignition timing of the distributor. The cam shaft of the distributor extends through the central hole of the mounting plate 15 in the usual manner, and co-acts in the conventional manner with an insulating heel member of the contact breaker assembly. The casing of the distributor is closed in use by an insulating cap carrying high tension output terminals disposed around its periphery, and a centrally disposed high tension input terminal.

I claim:

1. An ignition distributor including a hollow casing formed internally with a support surface and a groove, said groove extending radially into the wall of said casing from said support surface, a contact breaker assembly mounting plate supported on said support surface, and having a peripheral region which is engageable in said groove, a single resilient member engaged both with said casing and said mounting plate, and resiliently biasing said mounting plate both downwardly onto said support surface, and transversely so as to engage said peripheral region of said mounting plate in said groove, and, said peripheral region of said mounting plate and said groove being so shaped in relation to one another that said peripheral region engages in said groove with awedging actionv 2. An ignition distributor as claimed in claim 1 wherein said resilient member is a spring steel strip of generally L-shaped configuration, one limb of said strip engaging said casing and said other limb engaging said mounting plate. 7 V

3. An ignition distributor as claimed in claim 2 wherein the free end of said' one limb engages a shoulder on said inner surface of said casing. v

4. An ignition distributor as claimed in claim 2 wherein said other limb is secured to said mounting plate by a screw fastening device.

5. An ignition distributor as claimed in claim 2 wherein said other limb of said resilient member includes a portion extendinginto an aperture in said mounting plate said portion abutting said wall of said aperture.

6. An ignition distributor as claimed in claim 1 wherein said mounting plate is provided opposite'said peripheral region with a slot extending from the periphery of said mounting plate along a chord of said mounting plate so as to define a resilient ear integral with said mounting plate, clamping means being provided for urging said resilient ear ina direction away from the remainder of said mounting plate so as to' engage said resilient ear in said groove and so aid the action of said- 7 resilient member in clamping saidmounting plate in position in said casing.

7. An ignition distributor as claimed in claim 6 wherein the periphery of saidresilient car which engages in said groove is chamfered was to wedgingly engage said walls of the groove.

8. An ignition distributor as claimed in claim '6 wherein said clamping'means for urging said resilient ear in a direction away from said remainder of said mounting plate comprises a tapered screw which extends through said slot, said tapered screw serving also to secure said resilient member to said mounting plate. 1 

1. An ignition distributor including a hollow casing formed internally with a support surface and a groove, said groove extending radially into the wall of said casing from said support surface, a contact breaker assembly mounting plate supported on said support surface, and having a peripheral region which is engageable in said groove, a single resilient member engaged both with said casing and said mounting plate, and resiliently biasing said mounting plate both downwardly onto said support surface, and transversely so as to engage said peripheral region of said mounting plate in said groove, and, said peripheral region of said mounting plate and said groove being so shaped in relation to one another that said peripheral region engages in said groove with a wedging action.
 2. An ignition distributor as claimed in claim 1 wherein said resilient member is a spring steel strip of generally L-shaped configuration, one limb of said strip engaging said casing and said other limb engaging said mounting plate.
 3. An ignition distributor as claimed in claim 2 wherein the free end of said one limb engages a shoulder on said inner surface of said casing.
 4. An ignition distributor as claimed in claim 2 wherein said other limb is secured to said mounting plate by a screw fastening device.
 5. An ignition distributor as claimed in claim 2 wherein said other limb of said resilient member includes a portion extending into an aperture in said mounting plate said portion abutting said wall of said aperture.
 6. An ignition distributor as claimed in claim 1 wherein said mounting plate is provided opposite said peripheral region with a slot extending from the periphery of said mounting plate along a chord of said mounting plate so as to define a resilient ear integral with said mounting plate, clamping means being provided for urging said resilient ear in a direction away from the remainder of said mounting plate so as to engage said resilient ear in said groove and so aid the action of said resilient member in clamping said mounting plate in position in said casing.
 7. An ignition distributor as claimed in claim 6 wherein the periphery of said resilient ear which engages in said groove is chamfered so as to wedgingly Engage said walls of the groove.
 8. An ignition distributor as claimed in claim 6 wherein said clamping means for urging said resilient ear in a direction away from said remainder of said mounting plate comprises a tapered screw which extends through said slot, said tapered screw serving also to secure said resilient member to said mounting plate. 